1. Field of the Invention
The present invention relates to blade and frame assemblies for heavy power machines generally classified as bulldozers or roadgraders and more particularly the type known as a log skidder which is used for clearing or thinning timber in logging operations.
2. Description of the Prior Art
The class of heavy power machines described above is equipped with a front mounted blade which is swung vertically on a framework rotatably connected to the machine. The bulldozer uses the blade primarily for moving dirt so as to level or fill land areas. The skidder is a multi-purpose machine designed for cutting roadways in heavy stands of timber, mostly in hills or mountainous terrain and dragging logs out of the woods through gullies, swampy areas and around trees or stumps. When the logs are dragged or skidded to the roadside they are stacked in piles for loading onto logging trucks. For this type of work the skidder is constructed in two sections, a front drive section joined by a swivelling connection to an aft driving trailer section. A narrow blade is connected to a pair of elongated arms which is rotatably mounted at their distal ends on the front section adjacent to the operator's compartment. The blade is operated for movement in a vertical direction. A powerful winch mounted on the trailer has a brake drum for handling one or more steel cables. The cables are wrapped around several logs and skidded out of the trees, stumps and the like to a road previously cut and leveled by the same skidder. Skidding logs out of a thinned woods is a difficult task for the operator of a skidder for he is seldom permitted to turn the machine around among trees and stumps or to skid logs in a straight path to the road. The skidder blade being supported in front between the two front wheels will not clear some trees and makes it necessary to back up and reposition the machine several times. This will happen in spite of the fact that with a swivelling trailer and capability of virtually bending the skidder in an L-shape around a tree, the tree may be lodged in front of or between the blade and the framework and prevent the machine from getting free. When this occurs the tree has to be cut down involving a considerable loss of operational time. Another problem similar to this happens when a skidder slides sideways down a hill and catches a tree behind the blade. Again in this situation it is required to cut the tree down to free the machine. Yet another problem occurs when the skidder is required to use the blade to cut a roadway in the woods along a steep hillside. This becomes a very difficult task inasmuch as the narrow blade lays inside of the front tires whereupon the high side tire behind the blade rides on the upper portion of the bank and tilts the machine making it difficult to cut a level path. Preferably, the length of the blade is less than the width of the outside edge of the front tires by approximately the width of one tire. There is a daily problem with the conventional skidder blade where it is used to stack logs along the roadside. When the skidder has hauled logs to the roadside the machine is positioned so that the blade is parallel to the log to be lifted. If the blade is not positioned right the log is not balanced and the heavy or butt end will remain on the ground while the light end will swing up over the pile of logs. Then the operator will have to drop the log and reposition the machine and blade as many times as is necessary to lift it to the top of the pile.
In light of the foregoing description of the difficult problems occurring with the existing blade arrangement on the log skidder it is the object of the present invention to provide a laterally adjustable blade and frame which will solve these problems. The present invention can be manufactured inexpensively and is readily adaptable for installation on skidders and heavy equipment used in similar work.